Long-core experimental study of different displacement modes on fractured-vuggy carbonate reservoirs

Wenfang Li,Jiang Chen,Xiqun Tan,Ping Liu,Yun Li,Limin Wang 한국자원공학회 2018 Geosystem engineering Vol.21 No.2

It is difficult to utilize real fractured–vuggy carbonate cores to conduct long-core displacement experiments due to the special structures of fractured and vuggy. Aiming to not affect the porosity and permeability of the original core structure, a special filling method on the sunken space of the core surface was created to meet the requirements of long-core experiments. Long-core experiments of depletion drive, water flooding, gas drive, and water alternating gas (WAG) drive were performed to simulate the actual conditions of one-dimension oil reservoir and systematically study the influence of different development approaches on the recovery of vuggy carbonate reservoirs. Results show that the optimal conversion pressure of water flooding is between 80% bubble point and bubble point pressure. In the high-pressure and high water-cut stage, the development effect of gas–water alternative drive becomes significant, it can effectively reduce water cut and improve oil recovery. The most suitable and effective displacement mode is adopted depletion drive first and converts water flooding when the pressure decreases between 80% bubble point and bubble point pressure. When the water cut approximately reaches 80%, then WAG flooding is performed. The experiments provide data and technical support for the rational development of vuggy carbonate reservoirs.

IL-17 Imbalance Promotes the Pyroptosis in Immune-Mediated Liver Injury Through STAT3-IFI16 Axis

Wenfang Xu,Yanan Wang,Changzhong Jin,Weiyang Zhang,Jiangnan Chen,Xuefang Chen,Junli Gao,Junshun Gao,Hong Wang 대한면역학회 2023 Immune Network Vol.23 No.6

Autoimmune hepatitis (AIH) affects all age group and occurs mainly in women. Pyroptosis is a novel programmed cell death featured with cell bursting and release of proinflammatory cytokines. A deeper understanding of AIH pathogenesis will contribute to novel therapy for AIH patients. Here, we aimed to investigate the role of IL-17 in immune-mediated liver injury. The levels of cytokines were measured by ELISA, and mRNA levels of STAT3 and IFN gammainducible protein 16 (IFI16) were detected by PCR. Expressions of STAT3, IFI16, gasdermin D and cleaved caspase-1 were measured by western-blotting. Immunohistochemical staining and transmission electron microscopy were applied to evaluate liver histopathological changes of the treated mice. Our results showed that the levels of IFI16 was increased in hepatocytes treated with IL-17 protein, and further elevated after STAT3-overexpressed (STAT3-OE) lentivirus treatment. The levels of IFI16 were reduced in hepatocytes treated with IL-17 neutralizing Ab (nAb), but were significantly increased after STAT3-OE treatment. Pyroptosis was observed in hepatocytes treated with IL-17 protein, and further cell damage was observed after STAT3-OE lentivirus treatment. Liver damage was alleviated in mice treated with IL-17 nAb, however sever damage was experienced after STAT3-OE lentivirus treatment. A binding interaction between IFI16 and STAT3 was detected in IL-17 treated hepatocytes. Glutathione transaminase activity was enhanced in concanavalin A-induced AIH mice compared to the control group (p<0.01). IL-17 plays an important role in activating STAT3 and up-regulating IFI16, which may promote the pyroptosis in AIH-related liver injury through STAT3-IFI16 axis.

Expression, Purification, and Bioactivity of (GLP-1A2G)2-HSA Analogs in Pichia pastoris GS115

Wenfang Dou,Junshang Feng,Xiaomei Zhang,Hongyu Xu,Jinsong Shi,Zhenghong Xu 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.6

We developed (GLP-1A2G)2-HSA (GGH) analogsthat are resistant to degradation and also show high serumglucose-reducing activity in vivo. Five analogs with Nterminalextensions were designed based on the proteinGGH. Next, we constructed recombinant plasmids capableof expressing the five analogs in methylotrophic yeastPichia pastoris GS115. Expression reached 150 mg/L in asmall-scale incubation. Fusion proteins were successfullypurified from the supernatant using ultrafiltration concentration,affinity absorption chromatography, hydrophobicchromatography, ion exchange chromatography and gelfiltration. A single band was observed on SDS-PAGE andthe purity was 97%. Activity test results suggested thatboth A-GGH and G-GGH showed better activity in vitroand that their cAMP levels were significantly increased by10-fold compared to GGH without N-terminal extension. Additionally, A-GGH efficiently enhanced the glucoseloweringeffect, which was maintained after the administrationfor 24 h. A-GGH is a potential drug for treating type 2diabetes.

Simultaneous Improvement of Thermal Conductivity and Strength for Commercial A356 Alloy Using Strontium Modification Process

Kang Wang,Wenfang Li,Wenzhi Xu,Shengyu Hou,Shaodong Hu 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11

The Aluminum–Silicon (Al–Si) die-casting alloys, such as the commercial A356 alloy, are expected to be used in heat-sinkand the device with high thermal conductivity due to their high production efficiency of casting process. These fields alsorequired them to possess sound mechanical properties. To meet these demands, the Strontium (Sr) was often utilized tomodify the silicon phase. According to our current work, the secondary dendrite arm spacing of the α-Al grains prominentlywas decreased when 0.05%–0.25% strontium was added. The decrease of the secondary dendrite arm spacing (SDAS) lead tothe enhancement of the mechanical strength as well as the improvement of the thermal and electrical conductivity. When theSr dosage was 0.15% in the commercial A356 alloy, the strength and the thermal conductivity of the A356 alloy simultaneouslyreached the maximum value. The improvement of the electrical and thermal conductivity might by contributed by theformation of a good conductor, Al2Si2Srphase, on the Si surface. Further investigations suggested that the improvement ofthermal conductivity was mainly due to the modification effect of Sr on the eutectic Si phase, which enlarged the specificarea between the α-Al/eutectic Si interface. The WDS analysis indicated that the solubility of Si decreased in aluminummatrix by increasing in the Sr dosage. However, the excessive dosage of strontium would result in the coarsening of themodified silicon phase, deteriorating the strength and the thermal and electrical conductivity of the modified A356 alloys.

Removal of UO2 2+ from aqueous solution using halloysite nanotube-Fe3O4 composite

Yuantao Chen,Wenfang He,Wei Zhang,Chunlian Hu,Jian Wang,Pingping Wang 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.1

Halloysite nanotubes (HNTs) were modified with Fe3O4 to form novel magnetic HNTs-Fe3O4 composites, and the composites were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). The as-obtained results indicated that Fe3O4 nanoparticles were successfully installed on the surface of HNTs. The adsorption of UO2 2+ on HNTs-Fe3O4 was investigated as a function of solid content, contact time, pH, ionic strength and temperature by batch experiments. The consequences revealed that the adsorption of UO2 2+ onto HNTs-Fe3O4 was strongly dependent on pH and ionic strength. Equilibrium data fitted well with the Langmuir isotherm. The experimental results demonstrated that the adsorbents with HNTs-Fe3O4 had the largest adsorption capacity of 88.32mg/g for UO2 2+.

Optical absorption of a hydrogenic impurity in a disc-shaped quantum dot

Ruihao Wei,Wenfang Xie 한국물리학회 2010 Current Applied Physics Vol.10 No.3

Using the perturbation method and the effective-mass approximation, we studied a hydrogenic impurity confined in a disc-shaped quantum dot with a parabolic potential in the presence of an electric field. Both the electric field and the confinement effects on the transition energy and the oscillator strength were investigated. Based on the computed energies and wave functions, the linear, the third-order nonlinear and the total optical absorption coefficients were also calculated. The results show that the optical absorption coefficients obtained in a disc-shaped parabolic QD can reach the magnitude of 104/cm, which is 1–2 orders of magnitude higher than that in the case of a spherical parabolic QD. We found that the transition energy, the oscillator strength, the linear, the third-order nonlinear and the total optical absorptions of the hydrogenic impurity in a disc-shaped QD dependent strongly on the confinement strength, and the applied electric field intensity.

NONLINEAR OPTICAL PROPERTIES OF THE WURTZITE InGaN/AlGaN PARABOLIC QUANTUM DOT

TAIRONG CHEN,Wenfang Xie,Shijun Liang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.2

The linear and nonlinear optical properties in a wurtzite InxGa1-xN/AlyGa1-yN strained spherical quantum dot (QD) subjected to a uniform external electric field with a direction opposite to that of the built-in electric (BEF) within the framework of effective-mass approximation have been investigated. The results show that the BEF has great effects on the linear and nonlinear optical absorption coefficients (ACs) and refractive index (RI) changes. Moreover, the dependence of the linear and nonlinear optical properties on the In composition, on the Al composition and on the inner sphere radius has been studied in detail. It is indicated that the ACs and RI changes of the Wurtzite spherical QD have strongly affected by these factors. The results may make a significant contribution to designing some important photodetectors and photonic crystal devices.

Surface Self-Nanocrystallization of α+β Titanium Alloy by Surface Mechanical Grinding Treatment

Chuang Li,Wenfang Cui,Yusheng Zhang 대한금속·재료학회 2017 METALS AND MATERIALS International Vol.23 No.3

In this work, the heavy deformation was performed on Ti6Al4V alloy by using surface mechanical grindingtreatment (SMGT) in order to obtain surface nanocrystalline layer. The phase structure and microstructuresin the deformation zones were characterized by XRD, SEM and TEM. The nanocrystallization mechanisms ofα and α phase were clarified. The results show that a gradient structure including nano grain, quasi nanograinand micro-grains was achieved within the depth of 500 μm below the surface. The depth of nanocrystallineslayer was at least 20 μm. From the non deformation zone in the center to the heavy deformation zone close totreated surface, dislocation densities gradually increased. The original coarse grains gradually evolved intodislocation cell structures and subgrains through dislocation movement. In the depth of about 20 μm belowthe treated surface, the subgrains began to split into nano-scale grains with high angle grain boundaries bylattice rotation and tilting mechanisms. During SMGT, β phase deformed and refined prior to α phase, andinhibited the generation of twinning in α grain. The coordinated deformation between a and β phase promotedthe formation of nanocrystallines.

Electric field effect on the Raman scattering of a hydrogenic impurity in spherical quantum dot

Liangliang Lu,Wenfang Xie,Shijun Liang 한국물리학회 2011 Current Applied Physics Vol.11 No.6

Using the perturbation method and the effective mass approximation, we studied the combined effects of impurity and external electric field on Raman scattering in a spherical quantum dot with a parabolic potential. Based on the computed energies and wave functions, the differential cross-section involved in this process is investigated, and the selection rules are also calculated. Our results suggest that the scattering intensity is strongly affected by the impurity and external electric field considered in this work.

Microstructure and Properties of BaTiO3

Min Wang,Guoge Zhang,Wenfang Li,Xiaojun Wang 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.4

In this paper, we report the preparation of BaTiO3 (BT) ferroelectric films from barium hydroxide via micro arc oxidation (MAO) with additives. The BaTiO3 film was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-Raman spectroscopy, precision LCR measurements, and a Radiant Precision LC material analyzer. The results showed that the BT film was mainly composed of tetragonal-phase BaTiO3 , and the BT film was smooth, dense, and crack-free. At the frequency of 100 Hz, the film was found to possess a high dielectric constant of 245.3 and a low dielectric loss (tan δ) of 0.039. Compared with the BT film prepared without additives, the MAO-prepared film showed an increase of 61.1% in dielectric constant and a decrease of 59.4% in dielectric loss (tan δ). The BT film exhibited a saturated P–E hysteresis loop at room temperature.